When Mendeleev first proposed his periodic table in 1869 he left gaps for elements not yet discovered, but that he predicted should exist. One such gap was one beneath caesium, a position later found ...

It was recognized early on that the periodic table more or less fizzles out after ... Estimates suggest that there is only about 30 g of francium in the whole of the Earth's crust.

Highlighted in the Periodic Table below are some of the important elements that make a firework work. Click on the elements outlined to find out what their contributions are to a firework.